ON THE SOLUBILITY OF NITROCELLULOSE.

The solubility in ether-alcohol of varying proportions of five varieties of different nitrogen contents in the temperature in terval -20° to +30° has been determined, and the nitrogen contents of the dissolved and undissolved parts estimated separately. The results are as follows : Specimen A (N=13.23%) (Fig. 1 & 2, Japanese Original p. 255) 1) As the temperature falls, the solubility increases; the maximum solubility obtained with the composition ether 2 : alcohol 1 at -20° is twice as great as at an ordinary temperature.2) A solvent of the composition ether 2 : alcohol 1 shows the maximum solubility at any temperatures.3) Variation with temperature of the solubility is greatest in the solvent giving the maximum solubility, and correspondingly smaller in those of smaller solubilities.4) As the temperature falls, the nitrogen content of the dissolved part increases, e.g. for a solvent of ether 2 : alcohol 1, the nitrogen content at 30° is 11.82% and 12.38% at -20°, and it diminishes with its solubility. Hence the nitrogen contents of the mass, which may be considered to have dissolved owing to the fall of temperature, have been calculated.Fram the result above, it may be inferred that at 0°, the highly nitrated cellulose, gun-cotton, appears to begin to dissolve.Specimen B (N=12.69%) (Fig. 3 & 4, Japanese Original p. 258) This specimen, a pyrocollodion, dissolves better at a lower temperature and the solubility in solvents containing 14 to 50% alcohol varies from 60 to 100%, while the nitrogen content of the dissolved part remains the same.Specimen C (N=12.24%) and D (N=11.50%) (Fig. 5 & 6, Japanese Original p. 260) Both of these are highly soluble, and although the variation with the change of temperature of solubility is not distinct, the solubility appears to increase as the temperature falls; the former dissolves better in ether rich solvents, while the latter in alcohol rich solvents.Specimen E (N=10.97%) (Fig. 7 & 8. Japanese Original p. 261) Unlike the other four varieties, the solubility of this nitrocellulose increases with temperature and a mixture of equal volumes of ether and alcohol is a most favourable solvent.